My `04 Grand Cherokee has thrown the P1391 code, and from my research is either the Camshaft Position Sensor, or the Crankshaft Position Sensor. Is there any way to know for sure which one it is? The vehicle seems to run fine, gas mileage isn't great @16mpg (187,000+miles), but I don't have an issue starting, or idling. Any info to this problem is greatly appreciated. I know if I replace one, it's the other that's causing the code.
Thanks.